Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 272316
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
616 PM CDT WED AUG 27 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 429 PM CDT WED AUG 27 2014

MAIN CONCERNS FOR TONIGHT INTO EARLY ON THURSDAY WILL BE THE
POTENTIAL FOR HEAVY RAIN OVER PARTS OF THE AREA. CURRENT RADAR THIS
AFTERNOON SHOWING ONLY LIGHT SCATTERED SHOWERS REMAINING THROUGH THE
LOWER MISSOURI RIVER CORRIDOR. OTHERWISE...SEEING CONVECTIVE
DEVELOPMENT THROUGH SOUTH CENTRAL NEBRASKA ASSOCIATED WITH A
MIDLEVEL WAVE LIFTING INTO THE REGION...AND EXPECTING SOME OF THIS
ACTIVITY TO EVENTUALLY MAKE IT INTO OUR SOUTH LATER THIS EVENING. BY
LATER TONIGHT...CONVECTIVE POTENTIAL WILL THEN BE ENHANCED AS
MOISTURE TRANSPORT INCREASES WITH A STRENGTHENING LOW LEVEL JET
THROUGH EASTERN NEBRAKSA/FAR SOUTHEASTERN SOUTH DAKOTA AND
NORTHWESTERN IOWA. HOW AND WHERE ALL THIS COMES TOGETHER WILL
DETERMINE WHICH AREAS GET THE MOST RAINFALL...AND MODELS ARE STILL
IN SOME DISAGREEMENT ON THIS. HOWEVER...STILL LOOKS LIKE THE GENERAL
CONSENSUS WILL BE FOR THE HIGHEST QPF SOUTH OF INTERSTATE
90...LEANING TOWARD NORTHWESTERN IOWA. HI RES MODELS HAVE SLOWED
DOWN THE ONSET OF CONVECTION SOME...SO FOLLOWED SUIT AND DELAYED THE
TIMING JUST A BIT WITH THE BETTER STUFF DEVELOPING THROUGH THE MO
RIVER VALLEY TOWARD 06Z. PRECIPITABLE WATER AMOUNTS REMAIN JUST
EITHER SIDE OF TWO INCHES FOR TONIGHT INTO THURSDAY...SO STILL COULD
HAVE RAINFALL AMOUNTS OF 1 TO 3 INCHES THROUGH THE LOWER MO RIVER
VALLEY INTO NORTHWEST IOWA. CONTINUED TO DEBATE THROUGHOUT THE DAY
WHETHER A FLASH FLOOD WATCH WAS NEEDED FOR TONIGHT...THOUGH MOST
AREAS HAVE NOT RECEIVED RAINFALL SINCE THIS PAST WEEKEND...AND FLASH
FLOOD GUIDANCE VALUES ARE STILL PRETTY HIGH. THIS ON TOP OF SOME
UNCERTAINTY REMAINING ON WHERE A RELATIVELY NARROW BAND OF HIGHER
RAINFALL WILL OCCUR...DECIDED TO FORGO A WATCH AT THIS POINT. CANNOT
RULE OUT SOME ISOLATED URBAN FLOODING IF RAINFALL RATES GET HIGH
ENOUGH...AND WILL HAVE TO BE WATCHED ON FUTURE SHIFTS. RAINFALL WILL
CONTINUE THROUGH THURSDAY...TRENDING TO THE NORTH AND EAST
COLLOCATED WITH BETTER FORCING. THERMAL PROFILES WILL WILL WARM A
TAD FOR TONIGHT AND TOMORROW...WITH LOWS TONIGHT IN THE MID AND
UPPER 60S...WITH HIGHS ON THURSDAY MID/UPPER 70S.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 429 PM CDT WED AUG 27 2014

THE UPPER LEVEL TROUGH WILL MOVE THROUGH ON THURSDAY NIGHT INTO
FRIDAY AND WITH WEAK LOW TO MID LEVEL CONVERGENCE A DECENT THREAT
FOR SHOWERS AND THUNDERSTORMS TO CONTINUE. WHILE SEVERE WEATHER IS
NOT HIGHLY PROBABLE WITH FAIRLY POOR SHEAR THERE SHOULD BE DECENT
INSTABILITY TO SUPPORT PULSE HAILERS OR LOCALIZED HEAVY RAINFALL.

JUST A SMALL CHANCE FOR THUNDERSTORMS ON FRIDAY NIGHT INTO SATURDAY
AS A WEAK WAVE PASSES THROUGH. NOT ANTICIPATING ANY SEVERE THREAT AT
THIS TIME. HIGHS FRIDAY AND SATURDAY LIKELY TO BE IN THE LOWER TO
MIDDLE 80S WITH SOME SLIGHTLY COOLER READINGS ACROSS NORTHWEST IOWA
WHERE CLOUDS AND A POTENTIALLY COOLER AND MORE MOIST LOWER
ATMOSPHERE MAY KEEP TEMPERATURES FROM CLIMBING TOO MUCH.

IN THE OUTER PERIODS (SUNDAY THROUGH WEDNESDAY)...A STRONG SYSTEM
WITH WHAT APPEARS TO BE DECENT MOISTURE AND INSTABILITY SET TO MOVE
THROUGH THE AREA ON SUNDAY SO WILL CONTINUE WITH SOME PRETTY HIGH
POPS IN THE EASTERN HALF OF THE CWA. WILL ALSO NEED TO KEEP AN EYE
OUT FOR THE POTENTIAL FOR SEVERE THUNDERSTORMS. MONDAY THROUGH
WEDNESDAY NOT LOOKING LIKE ANY GREAT CHANCES FOR SHOWERS AND
THUNDERSTORMS BUT WILL KEEP SOME LOWER POPS IN MONDAY NIGHT INTO
TUESDAY AS SOME MID LEVEL WARM ADVECTION COULD CAUSE SOME
DEVELOPMENT. OTHERWISE TEMPERATURES FAIRLY SEASONAL AND LIKELY TO
COME IN JUST A BIT BELOW NORMAL.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY AFTERNOON)
ISSUED AT 616 PM CDT WED AUG 27 2014

IFR CONDITIONS WILL OVERSPREAD MOST OF THE REGION THIS EVENING AND
CONTINUE INTO THURSDAY. NORTHERN PARTS OF SOUTH DAKOTA AS WELL AS
LOCATIONS WEST OF THE JAMES RIVER VALLEY WILL SEE THE IFR CONDITIONS
IMPROVE TO MVFR QUICKEST TOMORROW MORNING WHILE PARTS OF SW
MINNESOTA AND NW IOWA WILL REMAIN IN IFR THROUGH THE TAF PERIOD.
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE AFTER ABOUT 4Z
WITH THE MOST WIDESPREAD COVERAGE LIKELY FROM ABOUT 9Z THROUGH 15Z.
THE BEST CHANCES FOR THUNDERSTORMS WITH HEAVY RAINFALL WILL BE AT
KFSD AND KABR.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...JM
LONG TERM...08
AVIATION...JM






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